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Diffstat (limited to 'src/lib.rs')
| -rw-r--r-- | src/lib.rs | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/src/lib.rs b/src/lib.rs new file mode 100644 index 0000000..7adc0c7 --- /dev/null +++ b/src/lib.rs @@ -0,0 +1,398 @@ +//! Demangle Rust compiler symbol names. +//! +//! This crate provides a `demangle` function which will return a `Demangle` +//! sentinel value that can be used to learn about the demangled version of a +//! symbol name. The demangled representation will be the same as the original +//! if it doesn't look like a mangled symbol name. +//! +//! `Demangle` can be formatted with the `Display` trait. The alternate +//! modifier (`#`) can be used to format the symbol name without the +//! trailing hash value. +//! +//! # Examples +//! +//! ``` +//! use rustc_demangle::demangle; +//! +//! assert_eq!(demangle("_ZN4testE").to_string(), "test"); +//! assert_eq!(demangle("_ZN3foo3barE").to_string(), "foo::bar"); +//! assert_eq!(demangle("foo").to_string(), "foo"); +//! // With hash +//! assert_eq!(format!("{}", demangle("_ZN3foo17h05af221e174051e9E")), "foo::h05af221e174051e9"); +//! // Without hash +//! assert_eq!(format!("{:#}", demangle("_ZN3foo17h05af221e174051e9E")), "foo"); +//! ``` + +#![no_std] +#![deny(missing_docs)] + +#[cfg(test)] +#[macro_use] +extern crate std; + +mod legacy; +mod v0; + +use core::fmt; + +/// Representation of a demangled symbol name. +pub struct Demangle<'a> { + style: Option<DemangleStyle<'a>>, + original: &'a str, + suffix: &'a str, +} + +enum DemangleStyle<'a> { + Legacy(legacy::Demangle<'a>), + V0(v0::Demangle<'a>), +} + +/// De-mangles a Rust symbol into a more readable version +/// +/// This function will take a **mangled** symbol and return a value. When printed, +/// the de-mangled version will be written. If the symbol does not look like +/// a mangled symbol, the original value will be written instead. +/// +/// # Examples +/// +/// ``` +/// use rustc_demangle::demangle; +/// +/// assert_eq!(demangle("_ZN4testE").to_string(), "test"); +/// assert_eq!(demangle("_ZN3foo3barE").to_string(), "foo::bar"); +/// assert_eq!(demangle("foo").to_string(), "foo"); +/// ``` +pub fn demangle(mut s: &str) -> Demangle { + // During ThinLTO LLVM may import and rename internal symbols, so strip out + // those endings first as they're one of the last manglings applied to symbol + // names. + let llvm = ".llvm."; + if let Some(i) = s.find(llvm) { + let candidate = &s[i + llvm.len()..]; + let all_hex = candidate.chars().all(|c| match c { + 'A'..='F' | '0'..='9' | '@' => true, + _ => false, + }); + + if all_hex { + s = &s[..i]; + } + } + + let mut suffix = ""; + let mut style = match legacy::demangle(s) { + Ok((d, s)) => { + suffix = s; + Some(DemangleStyle::Legacy(d)) + } + Err(()) => match v0::demangle(s) { + Ok((d, s)) => { + suffix = s; + Some(DemangleStyle::V0(d)) + } + Err(v0::Invalid) => None, + }, + }; + + // Output like LLVM IR adds extra period-delimited words. See if + // we are in that case and save the trailing words if so. + if !suffix.is_empty() { + if suffix.starts_with('.') && is_symbol_like(suffix) { + // Keep the suffix. + } else { + // Reset the suffix and invalidate the demangling. + suffix = ""; + style = None; + } + } + + Demangle { + style, + original: s, + suffix, + } +} + +/// Error returned from the `try_demangle` function below when demangling fails. +#[derive(Debug, Clone)] +pub struct TryDemangleError { + _priv: (), +} + +/// The same as `demangle`, except return an `Err` if the string does not appear +/// to be a Rust symbol, rather than "demangling" the given string as a no-op. +/// +/// ``` +/// extern crate rustc_demangle; +/// +/// let not_a_rust_symbol = "la la la"; +/// +/// // The `try_demangle` function will reject strings which are not Rust symbols. +/// assert!(rustc_demangle::try_demangle(not_a_rust_symbol).is_err()); +/// +/// // While `demangle` will just pass the non-symbol through as a no-op. +/// assert_eq!(rustc_demangle::demangle(not_a_rust_symbol).as_str(), not_a_rust_symbol); +/// ``` +pub fn try_demangle(s: &str) -> Result<Demangle, TryDemangleError> { + let sym = demangle(s); + if sym.style.is_some() { + Ok(sym) + } else { + Err(TryDemangleError { _priv: () }) + } +} + +impl<'a> Demangle<'a> { + /// Returns the underlying string that's being demangled. + pub fn as_str(&self) -> &'a str { + self.original + } +} + +fn is_symbol_like(s: &str) -> bool { + s.chars().all(|c| { + // Once `char::is_ascii_punctuation` and `char::is_ascii_alphanumeric` + // have been stable for long enough, use those instead for clarity + is_ascii_alphanumeric(c) || is_ascii_punctuation(c) + }) +} + +// Copied from the documentation of `char::is_ascii_alphanumeric` +fn is_ascii_alphanumeric(c: char) -> bool { + match c { + '\u{0041}'..='\u{005A}' | '\u{0061}'..='\u{007A}' | '\u{0030}'..='\u{0039}' => true, + _ => false, + } +} + +// Copied from the documentation of `char::is_ascii_punctuation` +fn is_ascii_punctuation(c: char) -> bool { + match c { + '\u{0021}'..='\u{002F}' + | '\u{003A}'..='\u{0040}' + | '\u{005B}'..='\u{0060}' + | '\u{007B}'..='\u{007E}' => true, + _ => false, + } +} + +impl<'a> fmt::Display for Demangle<'a> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + match self.style { + None => f.write_str(self.original)?, + Some(DemangleStyle::Legacy(ref d)) => fmt::Display::fmt(d, f)?, + Some(DemangleStyle::V0(ref d)) => fmt::Display::fmt(d, f)?, + } + f.write_str(self.suffix) + } +} + +impl<'a> fmt::Debug for Demangle<'a> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + fmt::Display::fmt(self, f) + } +} + +#[cfg(test)] +mod tests { + use std::prelude::v1::*; + + macro_rules! t { + ($a:expr, $b:expr) => { + assert!(ok($a, $b)) + }; + } + + macro_rules! t_err { + ($a:expr) => { + assert!(ok_err($a)) + }; + } + + macro_rules! t_nohash { + ($a:expr, $b:expr) => {{ + assert_eq!(format!("{:#}", super::demangle($a)), $b); + }}; + } + + fn ok(sym: &str, expected: &str) -> bool { + match super::try_demangle(sym) { + Ok(s) => { + if s.to_string() == expected { + true + } else { + println!("\n{}\n!=\n{}\n", s, expected); + false + } + } + Err(_) => { + println!("error demangling"); + false + } + } + } + + fn ok_err(sym: &str) -> bool { + match super::try_demangle(sym) { + Ok(_) => { + println!("succeeded in demangling"); + false + } + Err(_) => super::demangle(sym).to_string() == sym, + } + } + + #[test] + fn demangle() { + t_err!("test"); + t!("_ZN4testE", "test"); + t_err!("_ZN4test"); + t!("_ZN4test1a2bcE", "test::a::bc"); + } + + #[test] + fn demangle_dollars() { + t!("_ZN4$RP$E", ")"); + t!("_ZN8$RF$testE", "&test"); + t!("_ZN8$BP$test4foobE", "*test::foob"); + t!("_ZN9$u20$test4foobE", " test::foob"); + t!("_ZN35Bar$LT$$u5b$u32$u3b$$u20$4$u5d$$GT$E", "Bar<[u32; 4]>"); + } + + #[test] + fn demangle_many_dollars() { + t!("_ZN13test$u20$test4foobE", "test test::foob"); + t!("_ZN12test$BP$test4foobE", "test*test::foob"); + } + + #[test] + fn demangle_osx() { + t!( + "__ZN5alloc9allocator6Layout9for_value17h02a996811f781011E", + "alloc::allocator::Layout::for_value::h02a996811f781011" + ); + t!("__ZN38_$LT$core..option..Option$LT$T$GT$$GT$6unwrap18_MSG_FILE_LINE_COL17haf7cb8d5824ee659E", "<core::option::Option<T>>::unwrap::_MSG_FILE_LINE_COL::haf7cb8d5824ee659"); + t!("__ZN4core5slice89_$LT$impl$u20$core..iter..traits..IntoIterator$u20$for$u20$$RF$$u27$a$u20$$u5b$T$u5d$$GT$9into_iter17h450e234d27262170E", "core::slice::<impl core::iter::traits::IntoIterator for &'a [T]>::into_iter::h450e234d27262170"); + } + + #[test] + fn demangle_windows() { + t!("ZN4testE", "test"); + t!("ZN13test$u20$test4foobE", "test test::foob"); + t!("ZN12test$RF$test4foobE", "test&test::foob"); + } + + #[test] + fn demangle_elements_beginning_with_underscore() { + t!("_ZN13_$LT$test$GT$E", "<test>"); + t!("_ZN28_$u7b$$u7b$closure$u7d$$u7d$E", "{{closure}}"); + t!("_ZN15__STATIC_FMTSTRE", "__STATIC_FMTSTR"); + } + + #[test] + fn demangle_trait_impls() { + t!( + "_ZN71_$LT$Test$u20$$u2b$$u20$$u27$static$u20$as$u20$foo..Bar$LT$Test$GT$$GT$3barE", + "<Test + 'static as foo::Bar<Test>>::bar" + ); + } + + #[test] + fn demangle_without_hash() { + let s = "_ZN3foo17h05af221e174051e9E"; + t!(s, "foo::h05af221e174051e9"); + t_nohash!(s, "foo"); + } + + #[test] + fn demangle_without_hash_edgecases() { + // One element, no hash. + t_nohash!("_ZN3fooE", "foo"); + // Two elements, no hash. + t_nohash!("_ZN3foo3barE", "foo::bar"); + // Longer-than-normal hash. + t_nohash!("_ZN3foo20h05af221e174051e9abcE", "foo"); + // Shorter-than-normal hash. + t_nohash!("_ZN3foo5h05afE", "foo"); + // Valid hash, but not at the end. + t_nohash!("_ZN17h05af221e174051e93fooE", "h05af221e174051e9::foo"); + // Not a valid hash, missing the 'h'. + t_nohash!("_ZN3foo16ffaf221e174051e9E", "foo::ffaf221e174051e9"); + // Not a valid hash, has a non-hex-digit. + t_nohash!("_ZN3foo17hg5af221e174051e9E", "foo::hg5af221e174051e9"); + } + + #[test] + fn demangle_thinlto() { + // One element, no hash. + t!("_ZN3fooE.llvm.9D1C9369", "foo"); + t!("_ZN3fooE.llvm.9D1C9369@@16", "foo"); + t_nohash!( + "_ZN9backtrace3foo17hbb467fcdaea5d79bE.llvm.A5310EB9", + "backtrace::foo" + ); + } + + #[test] + fn demangle_llvm_ir_branch_labels() { + t!("_ZN4core5slice77_$LT$impl$u20$core..ops..index..IndexMut$LT$I$GT$$u20$for$u20$$u5b$T$u5d$$GT$9index_mut17haf9727c2edfbc47bE.exit.i.i", "core::slice::<impl core::ops::index::IndexMut<I> for [T]>::index_mut::haf9727c2edfbc47b.exit.i.i"); + t_nohash!("_ZN4core5slice77_$LT$impl$u20$core..ops..index..IndexMut$LT$I$GT$$u20$for$u20$$u5b$T$u5d$$GT$9index_mut17haf9727c2edfbc47bE.exit.i.i", "core::slice::<impl core::ops::index::IndexMut<I> for [T]>::index_mut.exit.i.i"); + } + + #[test] + fn demangle_ignores_suffix_that_doesnt_look_like_a_symbol() { + t_err!("_ZN3fooE.llvm moocow"); + } + + #[test] + fn dont_panic() { + super::demangle("_ZN2222222222222222222222EE").to_string(); + super::demangle("_ZN5*70527e27.ll34csaғE").to_string(); + super::demangle("_ZN5*70527a54.ll34_$b.1E").to_string(); + super::demangle( + "\ + _ZN5~saäb4e\n\ + 2734cOsbE\n\ + 5usage20h)3\0\0\0\0\0\0\07e2734cOsbE\ + ", + ) + .to_string(); + } + + #[test] + fn invalid_no_chop() { + t_err!("_ZNfooE"); + } + + #[test] + fn handle_assoc_types() { + t!("_ZN151_$LT$alloc..boxed..Box$LT$alloc..boxed..FnBox$LT$A$C$$u20$Output$u3d$R$GT$$u20$$u2b$$u20$$u27$a$GT$$u20$as$u20$core..ops..function..FnOnce$LT$A$GT$$GT$9call_once17h69e8f44b3723e1caE", "<alloc::boxed::Box<alloc::boxed::FnBox<A, Output=R> + 'a> as core::ops::function::FnOnce<A>>::call_once::h69e8f44b3723e1ca"); + } + + #[test] + fn handle_bang() { + t!( + "_ZN88_$LT$core..result..Result$LT$$u21$$C$$u20$E$GT$$u20$as$u20$std..process..Termination$GT$6report17hfc41d0da4a40b3e8E", + "<core::result::Result<!, E> as std::process::Termination>::report::hfc41d0da4a40b3e8" + ); + } + + #[test] + fn limit_recursion() { + use std::fmt::Write; + let mut s = String::new(); + assert!(write!(s, "{}", super::demangle("_RNvB_1a")).is_err()); + } + + #[test] + fn limit_output() { + use std::fmt::Write; + let mut s = String::new(); + assert!(write!( + s, + "{}", + super::demangle("RYFG_FGyyEvRYFF_EvRYFFEvERLB_B_B_ERLRjB_B_B_") + ) + .is_err()); + } +} |